Both are falsy, but nil represents “nothing,” while false is Boolean false.

Yukihiro "Matz" Matsumoto developed Ruby in the mid-1990s in Japan.

IRB (Interactive Ruby) is a REPL tool for writing and testing Ruby code interactively.

Mixins inject module methods into classes using include, enabling multiple inheritance behavior.

Ruby is a dynamic, object-oriented scripting language known for simplicity and productivity.

A Proc is a saved block that can be reused and passed around.

Modifying or adding methods to existing classes at runtime.

== checks value equality; eql? checks value and type equality.

Modules group reusable methods and constants; used for namespacing and mixins.

Dynamic typing, object-oriented, garbage collection, mixins, and readable syntax.

Instance variables begin with @ and are accessible throughout an object’s methods.

Everything in Ruby is an object, including numbers and classes.

self refers to the current object or context in which the code executes.

Ruby uses automatic garbage collection to manage memory and free unused objects.

puts adds a newline after output; print does not.

A block is an anonymous piece of code passed to methods, like closures.

Symbols are immutable, memory-efficient identifiers often used as hash keys.

A class defines an object’s blueprint with methods and attributes.

A lambda is a special Proc with strict argument checking and return behavior.

require loads external Ruby files or libraries into your program.

A hook method called when an undefined method is invoked on an object.

Use def method_name; end to define a method.

A gem is a packaged Ruby application or library distributed via RubyGems.

Creates getter and setter methods automatically for instance variables.

while, until, for, .each, and .times are common Ruby loops.